"Seriously, Tedd, we've spent a fair amount of time on this. This had better have SOMETHING to do with your overall character arc."
I like exploring the psychology of things, and in particular, non-human things with very different perspectives on life and reality.
It's difficult to write a character who is truly alien in terms of perspective, as it can be difficult to imagine it, and to make them relatable (though if the goal is to write a truly alien character, maybe being "relatable" isn't the goal).
Kevin's not that difficult, but he's not truly alien in personality, either. Still, he has his "I am definitely not human" quirks.